High resolution broadband beamforming based on the MVDR method

In this paper, a simple, yet efficient and practical, high-resolution beamforming procedure is presented. Using FFT, broadband signals obtained from a linear sonar array are decomposed into multiple narrowband signals. For each narrowband signal, multiple MVDR (minimum variance distortionless response) beams are formed to cover the whole azimuth range using proper phase shifts on the steering vector. The power sum of the beams formed in subbands is used to detect targets and estimate angle of arrival. Higher resolution is obtained using the proposed method, comparing to the conventional beamforming result.